The present invention relates to a method for detecting rates of rotation about, and optionally accelerations along, at least one, preferably two of three mutually perpendicular spatial axes x, y and z by means of a MEMS sensor, wherein at least one driving mass and at least one sensing mass are moveably arranged on a substrate, and the driving mass is moved at a driving frequency in an oscillating manner relative to the sensing mass, and also to a corresponding MEMS sensor with a substrate, with at least one driving mass which is arranged moveably and in oscillation parallel to the plane of the substrate in an x-y plane, with at least one sensing mass, with connection springs for connecting the at least one driving mass to the at least one sensing mass, and with at least one anchor and one anchor spring for connecting the at least one driving mass and/or the at least one sensing mass to the substrate, with drive elements for driving the driving mass/es in oscillation at a driving frequency relative to the sensing mass/es in order to subject them to Coriolis forces during a rotation of the substrate about an arbitrary spatial axis, and with sensing elements for detecting rotational movements and optionally accelerations movements of the substrate.
MEMS sensors are known for example as micro-gyroscopes, which are used for determining rotational movements about one or more axes in an orthogonal x-y-z-coordinate system. In order to be able to detect rotational movements of the system about each of the three axes, in the simplest case three micro-gyroscopes are necessary, each of which determines the rotational movement about a single axis. More expensive micro-gyroscopes are constructed in such a way that they can detect rotational movements about multiple axes. Basically, these gyroscopes work according to the principle that during a rotational movement of the entire system about an axis perpendicular to the driving motion, an oscillating driving mass generates a Coriolis force in the third axial direction. Given an appropriate mounting of the driving mass, this Coriolis force causes a deflection of the driving mass and, where applicable, of a sensing mass coupled to it. To the sensing mass in particular, sensing elements are assigned, which are normally plate capacitors or comb electrodes, which when their separation changes generate an electrical signal which is proportional to the rotational movement. The corresponding rotational movement can be detected by means of this electrical signal. A microgyroscope of this kind for three axes is known, for example, from TW 286201 BB.
US 2008/0053228 A1 discloses a sensor for detecting accelerations which can occur in three spatial axes. In this arrangement a sensing mass is moveably suspended in the space, and is deflected accordingly when accelerations of the sensor occur in one of the spatial axes. The deflection that occurred is determined in turn, by means of electrodes or by a deformation of the springs on which the sensing elements are suspended, and converted into an electrical signal.
A disadvantage of the sensors of the prior art is that to detect accelerations and rotational movements of the sensor, either different specialized sensors must be used, which only give information about the movements of the entire sensor unit in combination, or that very complicated sensors are necessary, which are difficult to manufacture and can be correspondingly vulnerable in operation. Also common to all these solutions is the fact that they are very cost intensive in their manufacture.